Sharpness at 85mm

For this test, the Tamron 28-85mm F2.8 Di III VXD G2 lens was attached to a Sony Alpha A7R IV body, which was in turn mounted to a sturdy tripod. Exposure delay mode was activated. Tonal and colour variance across the crops are due to change in natural light during the session.

The full frame at 85mm

Center sharpness is outstanding between f/2.8 and f/11. At f/16 sharpness drops off a little due to diffraction.

Edge sharpness is almost as good as in the centre, with the sharpest results between f/4 and f/11.

Aperture	Centre Crop	Edge Crop
f/2.8
f/4
f/5.6
f/8
f/11
f/16
f/22